Question

найдите значения выражения 15х-7у при х =1/5,у=3/21

Answer 1

5х-7у при х =1/5,у=3/21

15*1/5-7*3/21=3-1=2

Answer 2

$15 \times \frac{1}{5} - 7 \times \frac{3}{21} = 3 \times 1 - 1 \times \frac{1}{1} = \\ = 3 - 1 = 2$